Typewriting machine



April 4, 1939.

W. A. DOBSON TYPEWRITING MACHINE 2 Sheets-Sheet 1 Filed Dec.

Ap w. A. DOBSON TYPEWRITING MACHINE Filed Dec. 15, 1935 2 Sheets-Sheet 2 Patented Apr. 4, 1939 UNITED STATES ATENT OFFICE TYPEWRITIN G MACHINE Application December 13, 1935, Serial No. 54,192

5 Claims.

This invention relates to means for mounting and guiding the platen-carriage track-frame for case-shift movements, and for adjusting the track-frame for securing evenness of type-impressions.

There are provided opposite paired raceways extending in the direction of the case-shift movement at each end of the platen-frame, there being but a single ball playing in each pair of raceways. The lower swing-arms are fastened to a cross-shaft which is journaled in the framework, said swing-arms being hinged to the shiftable platen-supporting frame.

The side frames guide the carriage-track frame to adjust the platen further from or nearer to the type-faces.

The side frames also include adjustable shift stops, faced with cushioning material. The aforesaid swing-arms have spatulate stop faces.

The anti-friction bearings are adjustable for the purpose of securing proper coaction of the balls with the raceways. One of the raceways is provided with shims, which serve to take up play of the balls in both raceways simultaneously. The seating may guide the raceway parallel to the companion raceway, at all adjustments. Since the anti-friction bearings are based on the side frames, the latter may be freely moved for effecting adjustment of the carriage-track frame and platen relatively to the type-faces.

Other features and advantages will hereinafter appear.

In the accompanying drawings,

Figure 1 is a perspective View illustrating the novel case-shifting organization, some of the parts being shown in section.

Figure 2 is a front elevation showing the shiftframe, swing-arms, and the anti-friction bearings at the ends of said-shift-frame.

Figure 3 is a side elevation showing the shiftframe in upper-case position.

Figure 4 is a sectional plan showing details of the shift-frame, the raceways, and the mounting of the latter on the main frame side members.

Figure 5 is a crosssectional side elevation showing the case-shifting mechanism in lowercase position. 4

Type-bars it are pivoted in a segment H, mounted on a bridge l2, fastened to left and right side walls l3, I4 of the framework, which includes a rear cross-bar l5, a front cross-plate I6, and an intermediate cross-bar l'i. The usual letterfeeding carriage I8 includes a platen l9, journaled in side plates 29 upstanding from a truck 2| guided by means of anti-friction rollers 22 along rails 23.

Each type-bar It carries lower and upper case types 25, 26, and the carriage-rails 23 are parts of a shift-frame which includes end plates 28 rigidly joined to a cross-plate 29 having a flange 3%, to which the rear rail 23 is fastened by screws 3!. The front rail 23 is fastened by screws 33 to lugs 32 of said end plates.

The printing movements of the type-bars 10 are limited by means of the usual anvils or stopsurfaces 35.

The carriage-track frame 23, 28, 29 is mounted for shifting up and down, together with the carriage and platen, to bring into use either the upper-case types 26 or the lower-case types 25. The direction of the shift is inclined upwardly and rearwardly, parallel with the faces of the types.

For this purpose, the shifting carriage-track frame has a bottom mount and also a top mount, being guided by means of these mounts somewhat in the manner of a parallel motion device. The lower mount is a hail, consisting of a crossshaft 36 journaled in the side plates l3, M of the machine, and having forwardly-extending arms 31, which at their forward ends are jointly hinged by means of inwardly-projecting pintles 38 to said carriage-track frame, for lifting and lowering the same. The frame-ends 28 rest upon said pintles 38, being articulated thereto by openbottom slots 39, which permit ready assembling and disassembling the carriage-track frame upon the bail.

The means for mounting the carriage-track frame at its upper'portion, so as to facilitate and guide its up-and-down shifting, includes a pair of opposed anti-friction rolls 40, working between the ends of the carriage-track frame and the side frames of the typewriting machine.

Upon the outer faces of the ends 28 of the carriage-track frame, are fastened grooved guide-plates i l, by means of rivets 42. The balls run in these grooves, which form raceways H that are inclined upwardly and rearwarolly in parallelism with the type-bar segment I i. Companion raceways or grooves 43 are formed in mounts 44, which are rigidly supported by screws 45 upon the side plates i3, M of the main framework; these stationary mounts consisting of anchor-plates having grooves 43 therein.

Said anchor-plates M; are mounted for adjustment independently of each other forward or backward, to secure evenness of type-impressions throughout the line of typing. For this purpose,

each anchor-plate 44 is provided with a transverse slot 46, whereby it is mounted upon separated studs 41 that project inwardly from the side plates [3, 14. The slot extends at right angles to the type-bar segment I I, or at right angles to the line of the type-faces at Figure 5.

Adjustment of either mount 44 may be effected by an individual screw 48, threaded in the block or cross-bar 15, with its point bearing against the rear edge of the mount. This cross-bar I5 is held by screws 50 upon ears bent in from the side plates l3, I4. By turning the screw 48, adjustment of either mount 44 may be effected, and this adjustment may be secured by means of a set-screw 45, which extends through a slot 52 in the side plates [3 and I4.

To pinch the balls in the races, there are provided shims 53 which space the lefthand mount 44 from the side plate l3. The balls are thus held tightly, and so prevent endwise shake of the carriage-track frame. Adjustment is permitted upon the studs 41, and all is held fast by the screws 45.

The swingable frame, comprising the crossshaft 36, 37, and studs 38, guides the carriagetrack frame at its lower portion, the swing-arm studs 38 describing a path which substantially coincides with said case-shift direction.

It will also be seen that the novel anti-friction devices 40, M and 44 co-operate with the swingframe and minimize end-thrust friction. Each shift-frame plate has a raceway extending in case-shift direction, and a facing parallel raceway presented by the companion plate. A single anti-friction roller, in the form of a ball 40, plays in each pair of raceways M 43. The balls 4|] are pinched tightly.

Each shift-frame plate has the usual catch 64 whose hook 65 may be set under the pintle or stud 38 to normally prevent upward displacement of the shift-frame. Each catch 64 is secured to its plate by the usual screw-and-slot connection, which provides for close adjustment of the hook against the stud.

At each side of the machine, is a case-shift key 55 mounted upon a lever 56, fulcrumed upon .a stud. Each lever has an arm 51 for engaging a corresponding stud 38, and each shift-key lever has a spring which yieldably holds the lever in normal position determined by abutment of a tongue 58 of the lever with the lug 59 of the main frame. Said tongue 58 may be bent to adjust the shift-key-lever arm 51 to abut the swing-frame stud 38. Each swing-arm has, at its forward end, a portion 69 of spatulate form to make broad contact with lower and upper case-shift stops BI and 62, respectively. Each stop is of leather, and is retained in the cupped head of a screw 53 carried by an ear projecting laterally from the main frame. The screws 63 are turned to bring their respective case-shift stops toproper positions.

It will be seen that the swing-frame, in addition to equalizing the movements of the ends of the shift-frame for preventing skewing of the latter, also has the function of guiding the shiftframe in co-operation with the described antifriction devices. Each device may be limited to a single ball 45, and the raceways may be correspondingly short. The anti-friction bearings are effective to take up all end thrust on the carriagetrack frame.

The balls 40 are prevented from leaving the raceways by the caps 66 secured to the frame side plates I3 and M by the screws 61.

Variations may be resorted to within the scope of the invention, and portions of the improvements may be used without others.

Having thus described my invention, I claim:

1. In a portable typewriter, a main framework, a platen, a carriage, a trackframe for said carriage, means mounting and guiding said trackframe for case-shifting movement upon said framework, including a. rock-shaft journaled in said framework and having fastened thereto arms pivoted to the carriage-track frame, and a single anti-friction roller playing between a raceway-bearing in each frame-end and a. raceway-bearing in a companion member mounted directly upon said main framework, the rollers co-operating with said shaft, arms and members to guide the carriage-track frame in case-shifting direction, said raceway-bearings and single roller being capable of pivoting movement relative to one another, in accordance with the slight rocking of the frame due to the arcuate path of the points of connection of said arms with said frame, and case-shift stops mounted directly upon said main framework independently of said companion members for compactness, lightness and cheapness.

2. In a portable typewriter, a main framework having side walls, a platen, a carriage, a trackframe for said carriage, means mounting and guiding said track-frame for case-shifting movement upon said main framework, including a rock-shaft journaled in said framework and having fastened thereto arms pivoted to the carriage-track frame, a single anti-friction roller playing between a raceway bearing in each frame-end and a raceway bearing in a companion member presenting a mount carried on said main framework, the rollers co-operating with said shaft, arms and members to guide the carriage-track frame in case-shifting direction, said raceway bearings and single roller being capable of pivoting movement relative to one another, in accordance with the slight rocking of the frame due to the arcuate path of the points of connection of said arms with said frame, case-shift stops mounted directly upon said main framework independently of said companion members, for compactness, lightness and cheapness, the race-way-bearing mounts being fastened upon the side walls of said main framework, an adjustable guide for one of said mounts being provided in each of the opposite sides of the main framework of said machine, to guide said mount forwardly and backwardly, and means for effecting forward and backward adjustment of said mounts together with said roller-bearings, trackframe, platen-carriage and platen relatively to the printing plane of the platen at either side of the machine.

3. In a portable typewriter, a main framework, a platen, a carriage, a track-frame for said carriage, means mounting and guiding said trackframe for case-shifting movement upon said. main framework, including a rock-shaft journaled in said framework and having fastened thereto arms pivoted to the carriage-track frame, a single anti-friction roller playing between a raceway-bearing in each irame-end and a raceway-bearing in a companion member mounted directly upon said main framework, the rollers co-operating with said shaft, arms and members to guide the carriage-track frame in case-shifting direction, said raceway-bearings and single roller being capable of pivoting movement relative to one another, in accordance with the slight rocking of the frame due to the arcuate path of the points of connection of said arms with said frame, case-shift stops mounted directly upon said main framework independently of said companion members, for compactness, lightness and cheapness, and means for adjusting the raceway in either frame-end independently of said case-shift stops.

4. In a typewriting machine,.a main-frame, a carriage-track frame, means mounting and guiding said track frame for case-shift movement on said main-frame, including a rockable bail pivoted on said main-frame and having arms flexibly connected to said track frame, roller bearing units cooperating with said bail in support of said track frame, each of said bearing units including a first raceway on said trackframe, a second raceway on said main-frame and a single roller bearing riding in said first and second raceways, one of said raceways of each bearing unit presenting a mount adjustably carried on the companion frame, and means for adjusting said mounts to vary the position of said track frame relatively to the printing plane of the machine and independently of the rockable bail pivots, the track frame being rotatable about the connection thereof to said bail.

5. In a typewriting machine, a main-frame, a carriage-track frame, means mounting and guiding said track frame for case-shift movement on said main-frame, including a rockable bail pivoted on said main-frame and having arms flexibly connected to said track frame, roller bearing units cooperating with said bail in support of said track frame, each of said bearing units including a first raceway on said track, frame, a second raceway on said main-frame and a single roller riding in said first and second raceways, each of said second raceways presenting a mount adjustably carried on said main frame, a screw carried on said main frame and engaging said raceway mount, whereby to vary the position of said track frame relatively to the printing plane of the machine independently of the rockable bail pivots, the track frame being rotatable about the connection thereof to said bail.

WILLIAM A. DOBSON. 

